TeddyBench having problems while parsing tonies.json

I downloaded TeddyBench 1.6.9 and executed the exe file on my Windows 10 machine. After startup it says, that it had problems during ‘Parse tonie.json’. I can see, that it downloaded the file tonies.json and put it right besides the exe file. On first glance the content of the file seems proper.
I tried downloading it again via the manual trigger in the menu and the same error message showed up.
I purchased a used TonieBox and on the SD card there are still some files. These files are not recognized and shown with a picture even though the content while listening strongly suggests, that these files are original Tonie files.
I was able to reassign a file to new UID and the box properly started the playback, but the parsing issue persists.
Do I need to take additional steps when using TeddyBench? I was not able to find an user manuel or something comparable.